January 11, 2007

New Kostenki and South African finds in Science magazine (earliest occupation of Eurasia by modern humans)

I didn't see the papers online yet [they are now online], but from EurekAlert:
The excavation took place at Kostenki, a group of more than 20 sites along the Don River that have been under study for many decades. Kostenki previously has yielded anatomically modern human bones and artifacts dating between 30,000 and 40,000 years old, including the oldest firmly dated bone and ivory needles with eyelets that indicate the early inhabitants were tailoring animal furs to help them survive the harsh climate.
From the New York Times:
An international team of researchers reported today that the age of the South African skull, which they dated at about 36,000 years old, coincided with the age of and closely resembled the skulls of humans who were then living in Europe and the far eastern parts of Asia, even Australia.
The discovery of these resemblances lends some support to the idea that I have expressed previously that only a subset of modern humans (which I have called Afrasians) was responsible for the colonization of Eurasia. At the time frame in question, these resemblances would have been marked, since (i) intermixture with pre-existing populations (such as "Paleoafricans" or pre-moderns in Europe) did not have time to take place yet, and (ii) racial differentiation had only just begun. This paragraph says it all:
Because the Bushmen are well represented in the more recent archaeological record, Dr. Harvati said, they were expected to bear a close resemblance to the Hofmeyr skull. Instead, the skull was found to be quite distinct from all recent Africans, including the Bushmen, she said, and it has “a very close affinity” with fossil specimens of Europeans living in the Upper Paleolithic, the period best known for advanced stone tools and cave art.

“Much to my amazement,” Dr. Grine said in an interview, “the skull linked very closely with those from Europe at the time and not with South African remains 15,000 years on.”
The dissimilarity to recent Africans of the Hofmeyr skull can be easily explained if it is understood that recent Africans are not only descended from the "Afrasians" that I have spoken of, but also from the older "Paleofricans" whose existence can be inferred both by genetics (human mtDNA and Y-chromosomes are older than the ~40kya mark) and paleoanthropology (modern humans such as Omo and Herto are 100-200kya old).

It also stresses the idea that contrary to popular treatments such as Spencer Wells' Journey of Man, the appearance of African hunter-gatherers such as the Khoi-San should not be used as a model of what mankind's earliest African ancestors looked like.

Late Pleistocene Human Skull from Hofmeyr, South Africa, and Modern Human Origins

F. E. Grine et al.

The lack of Late Pleistocene human fossils from sub-Saharan Africa has limited paleontological testing of competing models of recent human evolution. We have dated a skull from Hofmeyr, South Africa, to 36.2 ± 3.3 thousand years ago through a combination of optically stimulated luminescence and uranium-series dating methods. The skull is morphologically modern overall but displays some archaic features. Its strongest morphometric affinities are with Upper Paleolithic (UP) Eurasians rather than recent, geographically proximate people. The Hofmeyr cranium is consistent with the hypothesis that UP Eurasians descended from a population that emigrated from sub-Saharan Africa in the Late Pleistocene.


Early Upper Paleolithic in Eastern Europe and Implications for the Dispersal of Modern Humans

M. V. Anikovich et al.

Radiocarbon and optically stimulated luminescence dating and magnetic stratigraphy indicate Upper Paleolithic occupation—probably representing modern humans—at archaeological sites on the Don River in Russia 45,000 to 42,000 years ago. The oldest levels at Kostenki underlie a volcanic ash horizon identified as the Campanian Ignimbrite Y5 tephra that is dated elsewhere to about 40,000 years ago. The occupation layers contain bone and ivory artifacts, including possible figurative art, and fossil shells imported more than 500 kilometers. Thus, modern humans appeared on the central plain of Eastern Europe as early as anywhere else in northern Eurasia.


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